ROBERT COSTA: President Trump confronts impeachment and history.

HOUSE SPEAKER NANCY PELOSI (D-CA): (From video.)

Our Founders' vision of a republic is under threat.

That is why today, as speaker of the House, I solemnly and sadly open the debate on the impeachment of the president of the United States.

ROBERT COSTA: President Trump is impeached, triggering political war in the House.

REPRESENTATIVE DOUG COLLINS (R-GA): (From video.)

I will fight this on process, which has been deplorable.

ROBERT COSTA: On the campaign trail.

PRESIDENT DONALD TRUMP: (From video.)

Nancy Pelosi's House Democrats - (boos) - have branded themselves with an eternal mark of shame, and it really is.

It's a disgrace.

ROBERT COSTA: And in the Senate.

SENATE MAJORITY LEADER MITCH MCCONNELL (R-KY): (From video.)

This particular House of Representatives has let its partisan rage create a toxic new precedent that will echo well into the future.

SENATE MINORITY LEADER CHARLES SCHUMER (D-NY): (From video.)

Leader McConnell is plotting the most rushed, least thorough, and most unfair impeachment trial in modern history.

ROBERT COSTA: Next.

ANNOUNCER: This is Washington Week.

Once again, from Washington, moderator Robert Costa.

ROBERT COSTA: Good evening.

The House of Representatives impeached President Trump on Wednesday, December 18th, on charges of abuse of power and obstruction of Congress.

Party leaders held their caucuses together; just a few Democrats broke ranks and no Republicans voted to impeach the president.

The Republican-controlled Senate is now poised to hold a trial that will determine whether the president stays in office, but Speaker Nancy Pelosi has so far delayed sending the articles over as Senate leaders negotiate the terms.

The key sticking point is this: whether Senate Majority Leader Mitch McConnell will allow testimony from Trump administration officials who defied subpoenas during the House inquiry.

REPRESENTATIVE ADAM SCHIFF (D-CA): (From video.)

The president of the United States should be tried.

And the question is now whether Senator McConnell will allow a fair trial in the Senate, whether the majority leader will allow a trial that involves witnesses and testimony and documents.

HOUSE SPEAKER NANCY PELOSI (D-CA): (From video.)

We cannot name managers until we see what the process is on the Senate side, and I would hope that that will be soon.

ROBERT COSTA: For the moment Leader McConnell isn't making any promises, and Congress is on recess until early January.

This week McConnell cast the pending trial as a political exercise.

SENATE MAJORITY LEADER MITCH MCCONNELL (R-KY): (From video.)

I'm not an impartial juror.

This is a political process.

There's not anything judicial about it.

Impeachment is a political decision.

The House made a partisan political decision to impeach; I would anticipate we will have a largely partisan outcome in the Senate.

I'm not impartial about this at all.

ROBERT COSTA: Joining me tonight to look ahead to that trial and back at this historic week are four top reporters: Molly Ball, national political correspondent for TIME Magazine; Ayesha Rascoe, White House reporter for NPR; Jerry Seib, executive Washington editor for The Wall Street Journal; and Philip Rucker, White House bureau chief for The Washington Post.

Molly, your book on the speaker, Pelosi by Molly Ball - I can't wait to read it - doesn't come out for a few months, but you've been studying her, reporting on her.

Why is she holding up the articles of impeachment?

MOLLY BALL: Well, what she has said is what she just said in that clip, that she needs to see what the Senate process is before she can decide who from the House to appoint to manage this.

But this really was not something that a lot of people saw coming, and having studied her I know she often has a trick up her sleeve but she never telegraphs it in advance.

So this was kind of a surprise move.

It was something some partisans had been speculating about but hadn't gotten a whole lot of traction until she did it.

And you know, now that both the House and Senate are out for a couple of weeks she's going to see what the president's reaction to this is and what the public's reaction to this is.

I think it's conveniently timed to create this sort of space for both sides to stew a little bit and see where the momentum is because, you know, she believes - the most important word in the speaker's vocabulary is "leverage," and she believes she has leverage in this situation because the president wants a trial to, in his - in his view, exonerate him.

And McConnell has actually, you know, laughed at this idea; he says, you don't have any leverage in this situation because we don't want to do this anyway, so you know, if you make us not do something we don't want to do that's fine.

But we know that the White House, the president does want a trial, and so - and so she does have a little bit of leverage, and we'll see whether she gets any response.

ROBERT COSTA: Phil, what kind of trial, though, does President Trump want at this point?

And Molly said the White House could be stewing; is President Trump stewing, and in this situation - this pause - could he actually end up saying to Democrats I'll provide some more documents and more witnesses?

PHILIP RUCKER: President Trump's been stewing for three years, so he's always stewing, but especially about this because as Molly said he wants the trial.

He wants to be exonerated, but not just to be exonerated and acquitted technically in the Senate but he wants defenders to come forward and put on a show and defend him for his conduct.

He also wants Republicans in the Senate to drag forward Democrats and give them a taste of what he feels like he experienced on the House side, so he wants Chairman Adam Schiff from the House to be dragged before the Senate and questioned by Republican senators.

He wants Hunter Biden, the former vice president's son, brought forward into the Senate.

There's back-and-forth negotiations going on right now between the White House and Leader McConnell and his office about these witnesses because McConnell has been opposed to having witnesses.

He thinks it's too risky.

Trump has long wanted some, and we'll see over the holidays whether they can find some equilibrium.

GERALD SEIB: Well, and I think the risky thing for the speaker here is that she, as in many of these cases, has a bit of a divide in her own caucus because liberal Democrats would like to stretch this out, hoping that maybe they will force some testimony by White House officials, which would be a new page in this whole drama, or that at a minimum they create this impression that the Senate trial will be a sham, what Republicans said the House impeachment process was.

But there are moderates in the Democratic caucus, 30 of them who come from districts that President Trump won in 2016, who would just as soon get this over with - go to the Senate, see it to the end, have the outcome that we all know is coming, which would be a vindication of some kind of President Trump, and then let them move on to their 2020 elections talking about other things.

So I think the speaker has competing interests here that she's trying to balance, and that's not easy in this case.

ROBERT COSTA: And there seem to be competing interests on the Republican side, as we've been talking about.

Leader McConnell has dismissed witnesses so far.

The White House is thinking about calling people like Chairman Schiff and Hunter Biden.

Where does this end up, Ayesha, based on your reporting?

AYESHA RASCOE: Well, you know, what was interesting this week is talking to people in the White House when these articles were held up.

The idea was like, oh, this makes Nancy Pelosi look so bad; this gives into the idea that this was all political; why - if this is such an urgent threat, why not go ahead and send them over?

But then you had the president send that tweet that says he wants a trial immediately, and so you can see why she probably does want to hold up a bit.

I think what you're going to see and what - I'm sure what Senator McConnell will be trying to do is trying to convince President Trump that it is not in his interest to have these witnesses come forward, and that when - if you try to call Hunter Biden and all these other people, that this could go badly for the White House, and that they will try to defend him and they are making the case - and I think that's probably why you have McConnell coming out saying he's not impartial, and Lindsey Graham and all these people being very defensive of the president, because they know he needs to hear that and that's what he wants.

But I don't think they want to give in on this having witnesses.

ROBERT COSTA: And it may be up to some of these senators, Republicans, the moderates - Senator Murkowski, Senator Collins, Senator Romney - and others on the fence on the Democratic side like Senator Jones of Alabama.

Who are you watching as they set the rules for this Senate trial?

They need a 51-vote threshold to set any kind of rule when it comes to witnesses.

MOLLY BALL: Yeah, I mean, all of the ones that you just named I think are the - are going to be if there are swing votes.

But what you see Senator McConnell really telegraphing is he doesn't think there is such a thing as a swing vote.

He thinks everybody's mind is made up, and I think by saying that so frequently and so definitively he's trying in a way to make that the reality, right?

If he can convince his own caucus that this is where they are going, that this is essentially a fait accompli, then I think he feels he's minimizing the waffling that some of those moderates might feel.

But as you said, there are some moderates in the caucus who may at some point have cold feet about this.

What we saw in the House, though, was that even the moderate House Republicans, even the House Republicans who have had questions about President Trump's conduct, in the end fell in line and were convinced by the president's defenses.

ROBERT COSTA: And we're talking about the party staying in line.

President Trump has certainly reveled in the GOP's continued support for him this week on several fronts.

They mostly backed a $1.4 trillion spending deal, which easily passed both chambers, and his revised North American trade agreement in a House vote, and of course they held on impeachment, which he noted at a rally in Michigan.

PRESIDENT DONALD TRUMP: (From video.)

We got - every single Republican voted for us.

So we had 198 - 229-198.

We didn't lose one Republican vote.

(Cheers.)

The Republican Party has never been so affronted, but they've never been so united as they are right now, ever.

(Cheers, applause.)

ROBERT COSTA: As the president wielded his power, Speaker Pelosi was able to hold her conference together, even moderate Democrats in battleground states, such as Elissa Slotkin of Michigan.

REPRESENTATIVE ELISSA SLOTKIN (D-MI): (From video.)

The president did something different than what President Nixon did, and President Clinton did, and President Johnson many, many, many years ago did.

And he gave the word to his administration to not produce any documents, to not respond to any subpoenas, and to not appear.

ROBERT COSTA: What kept people, House members like Elissa Slotkin, with Speaker Pelosi on this critical vote?

GERALD SEIB: Well, you - I think the impeachment process has kind of completed the process of tribalization of politics in the U.S., where everybody in each party puts on the home jersey, the blue jersey or the red jersey, and goes out on the field and plays for the team regardless of the circumstances, and regardless of what their misgivings might be.

And this is true in both parties.

It's interesting to remember that when President Trump began his presidential campaign in 2015 he almost ran as an independent.

He had disdain for the Republican Party, no regard for the Republican establishment, was hated by the Republican establishment.

And now here we are, three and a half years later.

That entire party is behind him.

That's what happens in American politics right now.

You get behind your team and you stay there, or you get punished from within your own party.

That's true in the Democratic Party and it's true in the Republican Party.

And I think that's the process we're seeing play out right now.

ROBERT COSTA: And talking about the GOP, what explains them going along with the protectionist-tilting trade deal, the new USMCA, the new version of NAFTA, going along with a trillion-dollar spending deal, and sticking with the president on impeachment?

PHILIP RUCKER: Just as Jerry said, this is a tribal moment in politics.

And all of those Republicans in the House know that if they turn on Trump, especially on impeachment, they're going to get a primary challenger the next day, they're going to have a hard time raising money, they're going to have the president tweeting attacks at them, they could potentially have the president going after them in rallies in their home districts.

They leave in fear of the president turning his political machine against them, because he has done that before.

It's the reason - one of the reasons why Bob Corker resigned from the Senate two years ago.

One of the reasons why Jeff Flake didn't run for reelection in Arizona last year.

You know, President Trump has such extraordinary control over the Republican Party.

GERALD SEIB: And let's not forget that some of those moderate senators who might be swing votes, there's still time for them to be challenged in a primary in the Republican Party in their home states before this vote happens.

They know that.

ROBERT COSTA: They're all still pretty quiet at the Capitol.

They keep saying they're going to be jurors.

But talk about President Trump this week.

He gave - he wrote that letter to Speaker Pelosi.

You called it, Phil, a window into his soul.

I saw it as a political rally on paper.

And he also had this rally in Michigan as he's being impeached in the House.

What was this week politically and personally for President Trump?

AYESHA RASCOE: Well, this week for President Trump was probably in many ways kind of his nightmare for the presidency.

He didn't want to be impeached, right?

Like this is - this is someone who - ROBERT COSTA: Against his brand.

(Laughs.)

AYESHA RASCOE: It's against his brand.

You know, you can't really sell impeachment, although they're trying a bit.

But yeah - (laughs) - like, this was something that - he wants to be an exceptional president.

He wants to be the best president there has ever been.

And now this week he is an impeached president.

And so I think that that - what you saw was him reacting to that and lashing out about that, really.

I mean, he had that two-hour rally in Michigan.

That was one of his longest rallies as president.

ROBERT COSTA: Was it also a snapshot of what we're going to see in 2020, grievance politics?

AYESHA RASCOE: Well, I think - I think that was going to happen, without a doubt.

But I think you're going to see it probably on steroids.

And he was already very worked up, even before impeachment came down the pike.

You saw him, like, tweeting more, and just getting more vicious, the way he was tweeting about the squad over the summer or the way he tweeted about Elijah Cummings.

This was something that had been - he had been going in a more personal direction, in a more grievance direction, like, for a very long time.

ROBERT COSTA: But Speaker Pelosi doesn't appear to be running on impeachment as her 2020 message for Democrats.

She's working with President Trump on the USMCA, and the spending deal, and prescription drug prices.

What does that tell you about the Democratic approach to next year's campaign season?

MOLLY BALL: She is obsessed with sending the message that Democrats are about governing.

And, remember, she resisted impeachment for a very long time - the better part of a year.

She held out against a lot of members of her caucus, who felt that the president deserved to be impeached, that it was a constitutional imperative for the Democratic Party.

And she held them off, and held them off, and held them off until the Ukraine situation was so compelling that it moved the caucus almost unanimously, and she went along with it.

But she really - her belief is that Democrats won the House because they ran on issues and they ignored Trump.

And so even though I think you would have to say that the backlash to Trump and the countermobilization against Trump was a huge part of the political dynamic in 2018, you had all the Democratic candidates who were on the same playbook.

They were talking about health care.

They were talking about jobs and wages.

And so obviously it will be a different story in 2020, when Trump is on the ballot and there is a Democratic candidate leading the message.

But she believes very strongly that those issues are still going to be what drives the electorate in 2020.

And the polling data that she and the other Democrats in the House are looking at is backing this up, is saying that this is pretty much a wash, the impeachment thing.

It has pretty much leveled out in terms of public opinion at about where Trump's approval rating is.

And by the time the election rolls around this won't be what we're talking about.

ROBERT COSTA: Jerry, you wrote recently about Prime Minister Johnson in England.

Are we seeing a new model for right-wing politics, populism and bigger government spending?

The Republicans, populists, supporting the trillion-dollar spending deal.

You saw Boris Johnson support the NHS and other spending over in the U.K. GERALD SEIB: Yeah, no, populism and nationalism have won the day.

And that's really what conservative politics has become.

And in that version of conservative politics, you simply don't worry about fiscal austerity.

That's not the formula.

The formula is don't worry about the deficit.

Your base is more working class.

They depend on government programs.

So fund those programs.

Boris Johnson is promising to do that in Britain right now.

Donald Trump promised that from 2015 on.

I'm not going to cut Social Security.

I'm not going to cut Medicare.

He never talks about the budget deficit, which is a trillion dollars a year now, because that's not what populist politics is about.

ROBERT COSTA: And, Phil, the president, when he looks at his own party he sees his own power and popularity with the GOP's core voters.

But he's giving them what they want on judges.

You see some grumbling on the right, the op-ed today in Christianity Today, an influential Evangelical magazine founded by the late Billy Graham, saying President Trump's out of line and should be removed from office.

But you see generally on the spending bill, judges, and a range of other issues, they're getting what they want even if they don't totally approve of his conduct.

PHILIP RUCKER: Exactly.

And it's one of the reasons that the president has been so deliberate, and the vice president too - Pence - about checking these boxes with the base, about pushing the judges and making that a priority for three years now, and all sorts of other issues, because they're trying to hold them tight heading into the next campaign.

ROBERT COSTA: And on Thursday night our colleagues at the PBS NewsHour and POLITICO hosted the latest Democratic debate.

South Bend, Indiana Mayor Pete Buttigieg has gained in recent Iowa polling, but he faced scrutiny from his rivals, such as Senator Elizabeth Warren of Massachusetts.

SENATOR ELIZABETH WARREN (D-MA): (From video.)

The mayor just recently had a fundraiser that was held in a wine cave full of crystals and served $900-a-bottle wine.

Think about who comes to that.

SOUTH BEND, INDIANA MAYOR PETE BUTTIGIEG (D): (From video.)

According to Forbes Magazine, I'm the - literally the only person on this stage who's not a millionaire or a billionaire.

(Laughter, cheers, applause.)

This is important.

This is the problem with issuing purity tests you cannot yourself pass.

ROBERT COSTA: Ayesha, a night of fireworks out in California.

What did that exchange tell us about the Democratic race, and in particular Mayor Buttigieg and his place in this contest?

AYESHA RASCOE: Well, it showed that Buttigieg is the one who is out in front, and that's why they're going after him, right?

Elizabeth Warren is going after him because he is a threat to her.

And so - but it also showed that kind of the dangers of that.

Like, she went after him, but he also pointed out that even though she's trying to take this high ground of saying that she's not getting these - she's not courting these big-dollar donors like he is, he pointed out that she brought over money from her Senate campaign and that she is actually - she has more money than he has and all of these things, that she's trying to set this purity test and that he is actually the one that is just - he's not focused on just meeting these demands; he's focused on doing what he has to do to win this election.

And so that's what he did.

I don't know whether that - I don't - I feel like it came out as a wash for really the both of them.

I don't know if either one of them really distinguished themselves.

I do think Amy Klobuchar, when she was going after Buttigieg, I think she did stand out and I think she was able to kind of point out some very key things, that one of the key things that he says is that he can win in the Midwest and she's pointing out you're a mayor.

ROBERT COSTA: Phil, when you're talking to your White House sources behind the scenes and you're trying to get a read on Vice President Biden's performance, do they see him as fading or steady?

PHILIP RUCKER: They see him as fading.

They were very worried about Biden at the onset, and frankly that's one of the reasons why President Trump is in this impeachment mess, and Trump has remained fixated on Biden because he continues to see Biden as a threat.

But the people working for Trump, his political advisors, are increasingly of the belief that Biden may not be the Democratic nominee.

They've been thinking a lot about Warren lately.

They're keeping an eye on Buttigieg, who they've not totally figured out how to run against.

Bloomberg looms as a bit of a threat.

They realize Biden could be the nominee, but he's not the singular focus that he was at the onset of the Democratic primary race.

GERALD SEIB: I actually think Amy Klobuchar, though, is the candidate who had the best night at the debate and the one who has the potential to sneak in the backdoor in Iowa.

And she's a problem in terms of profile for the president, I think, a moderate woman from the upper industrial Midwest, the precise part of the country that the president needs to win again to win a second term.

I'm not saying she's going to win Iowa or the nomination; I'm saying it's a very fluid field right now.

And there are three people trying to walk through the same door out of Iowa: Amy Klobuchar, Elizabeth Warren, and Pete Buttigieg.

That's why they were going after each other at the debate this week.

ROBERT COSTA: And Senator Warren for months has often stayed in her lane, focused on her message, yet took on Mayor Buttigieg.

Why did she do that, and where is she in this race?

MOLLY BALL: Well, I think, you know, she went through - we saw her poll numbers really nosedive when she was caught up on the healthcare issue and really got down a rabbit hole that she had a hard time getting out of.

But what she's realized - and I think you see it also where she's been on the stump attacking Mike Bloomberg very aggressively - she has realized that she can go back to that populist message that is about basically class warfare, and that is something - that's a message that she's good at, that's a message that she's comfortable with, and it is a substantive message.

It really is the backbone of her agenda, what she calls an anticorruption agenda.

It is very much about getting money out of politics.

It is very much about, you know, giving access to people who don't always have access to politicians.

She talks about the selfie line - they're not really selfies - (laughs) - but - ROBERT COSTA: What do you mean they're not really selfies?

MOLLY BALL: Because she's not taking them.

(Laughter.)

It's only if you take it.

ROBERT COSTA: The picture line.

MOLLY BALL: But the point being - the point being she's trying to run a sort of left-populist campaign, as is by the way Bernie Sanders.

Let's not forget that he's still pretty high up there in the polls too, so.

ROBERT COSTA: That is so true.

Senators Sanders, you look at almost every poll he's up there, not necessarily leading.

But is he a serious contender for this nomination?

He came close to being a serious - he was a serious contender in 2016.

AYESHA RASCOE: Well, he's certain a contender, and certainly his supporters will let you know that they feel like he's not getting the attention that he deserves.

I think we will have to see what happens in Iowa and whether he can kind of - whether he can pick up some momentum.

I mean, he has momentum, but whether he'll be able - whether he'll be able to translate that into support where it matters in these caucuses and in the primaries.

ROBERT COSTA: And when you look at that stage - and Senator Sanders talked about the issue of race - the Democratic Party facing a challenge when people of color are not making it onstage for the debate.

How are they grappling with that in terms of the field?

AYESHA RASCOE: I think it's a serious issue, and really when they were asked about questions on race yesterday, I mean, you could tell even with the questions that - when Sanders was asked about race, a lot of that he just kind of went back to, you know, healthcare and he's going to just work for everybody and make sure everybody gets a fair shake.

I think - and he even said at one point, yes, I'm a white male.

I think that that messaging can be difficult if you're trying to reach out to your base and get your base energized, and a lot of your base is not white.

And so I don't know that the Democrats have really figured out how to address that.

ROBERT COSTA: You mentioned Mayor Bloomberg.

He wasn't onstage, but he is spending a boatload of money on television advertising and he's inching up in national polling.

Where is his campaign moving?

PHILIP RUCKER: You know, Bob, he's focused on the second round of voting.

So you start in Iowa, New Hampshire, South Carolina, Nevada - those first four early states - and Bloomberg is banking literally that he can spend money in the states to come after that - California, Texas - big states where it costs tens of millions of dollars to run a credible advertising campaign, and clobber the field there, rack up delegates, and become a force by the time the convention rolls around.

And one of the things he's banking on is that the field is still fluid coming out of those four early states.

So you might have a Klobuchar win Iowa, you might have a Bernie Sanders win New Hampshire, you might have a Biden win South Carolina, and then who's the leader?

Bloomberg comes in with his money.

ROBERT COSTA: It's going to be quite a January, a February: a Senate trial potentially - we'll see if those articles go over - and then a presidential race.

Stick with us, but thanks now for sharing your evening with us.

We have to leave it there.

And make sure to check out our Washington Week Extra.

We will continue this discussion on the debate.

It airs live on our social media and is later posted on our website.

I'm Robert Costa.

Enjoy the holidays.